While EUV systems equipped with a 0.33 Numerical Aperture (NA) lens are readying to start high volume manufacturing, ASML and Zeiss are in parallel ramping up their activities on an EUV exposure tool with an NA of 0.55.
The purpose of this high-NA scanner, targeting an ultimate resolution of 8nm, is to extend Moore’s law throughout the next decade.
A novel lens design, capable of providing the required Numerical Aperture, has been identified; this lens will be paired with new, faster stages and more accurate sensors enabling the tight focus and overlay control needed for future process nodes.
In this paper an update will be given on the status of the developments at Carl Zeiss and ASML. Next to this, we will address several topics inherent in the new design and smaller target resolution: M3D effects, polarization, focus control and stitching.
With the introduction of its fifth-generation NXE:3400B scanner, ASML brought EUV to High- Volume Manufacturing for 7 nm node lithography and beyond with full support of pellicle. This paper presents an update on lithographic performance results obtained with the NXE:3400B, characterized by an NA of 0.33, a Pupil Fill Ratio (PFR) of 0.2 and throughput capability of 125 wafers per hour. Advances in source power and system availability have enabled a continued increase of productivity. To maximize the number of yielding dies per day excellent Overlay, Focus, and Critical Dimension (CD) control have been realized, combining intrinsic tool stability with holistic control schemes. We will also show matching performance for both Overlay and Imaging, and further improvements in Focus Process Dependencies for the 5nm node.
While 0.33NA EUV systems are readying to start volume manufacturing, ASML and Zeiss are ramping up development activities on a 0.55NA EUV exposure tool, extending Moore’s law throughout the next decade. A novel, anamorphic lens design, has been developed to provide the NA; this lens will be paired with new, faster stages and more accurate sensors and the tight focus and overlay control needed for future process nodes. This paper presents an overview of the target specifications, key technology innovations and imaging simulations demonstrating the advantages as compared to 0.33NA and showing the capabilities of ASML’s next generation EUV systems.
While EUV systems equipped with a 0.33 Numerical Aperture lenses are readying to start volume manufacturing, ASML and Zeiss are ramping up their activities on a EUV exposure tool with Numerical Aperture of 0.55.
The purpose of this scanner, targeting an ultimate resolution of 8nm, is to extend Moore’s law throughout the next decade.
A novel, anamorphic lens design, capable of providing the required Numerical Aperture has been investigated; This lens will be paired with new, faster stages and more accurate sensors enabling Moore’s law economical requirements, as well as the tight focus and overlay control needed for future process nodes.
The tighter focus and overlay control budgets, as well as the anamorphic optics, will drive innovations in the imaging and OPC modelling.
Furthermore, advances in resist and mask technology will be required to image lithography features with less than 10nm resolution.
This paper presents an overview of the target specifications, key technology innovations and imaging simulations demonstrating the advantages as compared to 0.33NA and showing the capabilities of the next generation EUV systems.
While EUV systems equipped with a 0.33 Numerical Aperture lenses are readying to start volume manufacturing, ASML and Zeiss are ramping up their development activities on a EUV exposure tool with Numerical Aperture greater than 0.5. The purpose of this scanner, targeting a resolution of 8nm, is to extend Moore’s law throughout the next decade.<p> </p> A novel, anamorphic lens design, has been developed to provide the required Numerical Aperture; this lens will be paired with new, faster stages and more accurate sensors enabling Moore’s law economical requirements, as well as the tight focus and overlay control needed for future process nodes. <p> </p>The tighter focus and overlay control budgets, as well as the anamorphic optics, will drive innovations in the imaging and OPC modelling, and possibly in the metrology concepts.<p> </p> Furthermore, advances in resist and mask technology will be required to image lithography features with less than 10nm resolution.<p> </p> This paper presents an overview of the key technology innovations and infrastructure requirements for the next generation EUV systems.
NXE:3300B scanners have been operational at customer sites since almost two years, and the NXE:3350B, the 4th generation EUV system, has started shipping at the end of 2015. All these exposure tools operate using MOPA pre-pulse source technology, which enabled significant productivity scaling, demonstrated at customers and at ASML. Having achieved the required throughput to support device development, the main priority of the ASML EUV program has shifted towards improving stability and availability. Continuous progresses in defectivity reduction and in the realization of a reticle pellicle are taking place at increased speed. Today’s overlay and imaging results are in line with the requirements of 7nm logic devices; Matched Machine overlay to ArF immersion below 2.5 nm and full wafer CDU performance of less than 1.0nm are regularly achieved. The realization of an intensity loss-less illuminator and improvements in resist formulation are significant progress towards enabling the use of EUV technology for 5nm logic devices at full productivity. This paper will present an overview of the status of the ASML EUV program and product roadmap by reviewing the current performance and on-going developments in productivity, imaging, overlay and mask defectivity reduction.
This paper describes the development and evolution of the critical architecture for a laser-produced-plasma (LPP) extreme-ultraviolet (EUV) source for advanced lithography applications in high volume manufacturing (HVM). In this paper we discuss the most recent results from high power sources in the field and testing on our laboratory based development systems, and describe the requirements and technical challenges related to successful implementation of those technologies on production sources. System performance is shown, focusing on pre-pulse operation with high conversion efficiency (CE) and with dose control to ensure high die yield. Finally, experimental results evaluating technologies for generating stable EUV power output for a high volume manufacturing (HVM) LPP source will be reviewed.
Multiple NXE:3300 are operational at customer sites. These systems, equipped with a Numerical Aperture (NA) of 0.33, are being used by semiconductor manufacturers to support device development. Full Wafer Critical Dimension Uniformity (CDU) of 1.0 nm for 16nm dense lines and 1.1 nm for 20nm isolated space and stable matched overlay performance with ArF immersion scanner of less than 4nm provide the required lithographic performance for these device development activities. Steady progresses in source power have been achieved in the last 12 months, with 100Watts (W) EUV power capability demonstrated on multiple machines. Power levels up to 90W have been achieved on a customer machine, while 110W capability has been demonstrated in the ASML factory. Most NXE:3300 installed at customers have demonstrated the capability to expose 500 wafers per day, and one field system upgraded to the 80W configuration has proven capable of exposing 1,000 wafers per day. Scanner defectivity keeps being reduced by a 10x factor each year, while the first exposures obtained with full size EUV pellicles show no appreciable difference in CDU when compared to exposures done without pellicle. The 4<sup>th</sup> generation EUV system, the NXE: 3350, is being qualified in the ASML factory.
The first NXE3300B systems have been qualified and shipped to customers. The NXE:3300B is ASML’s third generation EUV system and has an NA of 0.33. It succeeds the NXE:3100 system (NA of 0.25), which has allowed customers to gain valuable EUV experience. Good overlay and imaging performance has been shown on the NXE:3300B system in line with 22nm device requirements. Full wafer CDU performance of <1.5nm for 22nm dense and iso lines at a dose of ~16mJ/cm2 has been achieved. Matched machine overlay (NXE to immersion) of around 3.5nm has been demonstrated on multiple systems. Dense lines have been exposed down to 13nm half pitch, and contact holes down to 17nm half pitch. 10nm node Metal-1 layers have been exposed with a DOF of 120nm, and using single spacer assisted double patterning flow a resolution of 9nm has been achieved.<p> </p> Source power is the major challenge to overcome in order to achieve cost-effectiveness in EUV and enable introduction into High Volume Manufacturing. With the development of the MOPA+prepulse operation of the source, steps in power have been made, and with automated control the sources have been prepared to be used in a preproduction fab environment.<p> </p> Flexible pupil formation is under development for the NXE:3300B which will extend the usage of the system in HVM, and the resolution for the full system performance can be extended to 16nm. Further improvements in defectivity performance have been made, while in parallel full-scale pellicles are being developed.<p> </p> In this paper we will discuss the current NXE:3300B performance, its future enhancements and the recent progress in EUV source performance.
As EUV approaches high volume manufacturing, reticle defectivity becomes an even more relevant topic for further investigation. Current baseline strategy for EUV defectivity management is to design, build and maintain a clean system without pellicle. In order to secure reticle front side particle adders to an acceptable level for high volume manufacturing, EUV pellicle is being actively investigated. Last year ASML reported on our initial EUV pellicle feasibility. In this paper, we will update on our progress since then. We will also provide an update to pellicle requirements published last year. Further, we present experimental results showing the viability and challenges of potential EUV pellicle materials, including, material properties, imaging capability, scalability and manufacturability.
This paper describes the development of a laser-produced-plasma (LPP) extreme-ultraviolet
(EUV) source for advanced lithography applications in high volume manufacturing. EUV
lithography is expected to succeed 193nm immersion double patterning technology for sub-
20nm critical layer patterning. In this paper we discuss the most recent results from high
power testing on our development systems targeted at the 250W configuration, and describe
the requirements and technical challenges related to successful implementation of these
technologies. Subsystem performance will be shown including Conversion Efficiency (CE),
dose control, collector protection and out-of-band (OOB) radiation measurements. This
presentation reviews the experimental results obtained on systems with a focus on the topics
most critical for a 250W HVM LPP source.
Laser produced plasma (LPP) light sources have been developed as the primary approach for EUV scanner imaging of circuit features in sub-20nm devices in high volume manufacturing (HVM). This paper provides a review of development progress and readiness status for the LPP extreme-ultra-violet (EUV) source. We present the latest performance results from second generation sources, including Prepulse operation for high power, collector protection for long lifetime and low cost of ownership, and dose stability for high yield. Increased EUV power is provided by a more powerful drive laser and the use of Prepulse operation for higher conversion efficiciency. Advanced automation and controls have been developed to provide the power and energy stability performance required during production fab operation. We will also discuss lifetesting of the collector in Prepulse mode and show the ability of the debris mitigation systems to keep the collector multi-layer coating free from damage and maintain high reflectivity.
All six NXE:3100, 0.25 NA EUV exposure systems are in use at customer sites enabling device development and cycles
of learning for early production work in all lithographic segments; Logic, DRAM, MPU, and FLASH memory. NXE
EUV lithography has demonstrated imaging and overlay performance both at ASML and end-users that supports sub-
27nm device work. Dedicated chuck overlay performance of <2nm has been shown on all six NXE:3100 systems.
The key remaining challenge is productivity, which translates to a cost-effective introduction of EUVL in high-volume
manufacturing (HVM). High volume manufacturing of the devices and processes in development is expected to be done
with the third generation EUV scanners - the NXE:3300B. The NXE:3300B utilizes an NA of 0.33 and is positioned at a
resolution of 22nm which can be extended to 18nm with off-axis illumination. The subsystem performance is improved
to support these imaging resolutions and overall productivity enhancements are integrated into the NXE platform
consistent with 125 wph. Since EUV reticles currently do not use a pellicle, special attention is given to reticle-addeddefects
performance in terms of system design and machine build including maintenance procedures.
In this paper we will summarize key lithographic performance of the NXE:3100 and the NXE:3300B, the NXE platform
improvements made from learning on NXE:3100 and the Alpha Demo Tool, current status of EUV sources and
development for the high-power sources needed for HVM.
Finally, the possibilities for EUV roadmap extension will be reviewed.
ASML's NXE platform is a multi-generation TWINSCAN™ platform using an exposure wavelength of 13.5nm,
featuring a plasma source, all-reflective optics, and dual stages operating in vacuum. The NXE:3100 is the first product
of this NXE platform. With a 0.25 NA projection optics, a planned throughput of 60 wafers/hr and dedicated chuck
overlay of 4 nm, the NXE:3100 is targeted for extreme ultraviolet lithography (EUVL) implementation at 27nm halfpitch
(hp) and below. The next generation NXE tools utilize a 0.33NA lens and include off-axis illumination for high
volume manufacturing at a resolution down to 16nm hp and a targeted throughput of >100 wafers/hr. We share details
of the performance of the 0.25NA lithography products in terms of imaging, overlay, throughput, and defectivity. We
will show that we have met the required imaging performance associated with the 27nm hp node. We will also include a
summary of the EUV source development, which is a key enabler for cost-effective introduction of EUVL into highvolume
manufacturing. Finally, we will highlight some of the technical changes we introduced to enable the transition
from 27 to 22nm lithographic performance while introducing our 0.33NA Step & Scan system, the NXE:3300B.
With the 1st NXE:3100 being operational at a Semiconductor Manufacturer and a 2nd system being shipped at the time of
writing this paper, we enter the next phase in the implementation of EUV Lithography. Since 2006 process and early
device verification has been done using the two Alpha Demo Tools (ADT's) located at IMEC in Leuven, Belgium and at
the CSNE in Albany, New York, USA. Now process integration has started at actual Chipmakers sites. This is a major
step for the development and implementation of EUVL. The focus is now on the integration of exposure tools into a
manufacturing flow, preparing high volume manufacturing expected to start in 2013.
While last year's NXE:3100 paper focused on module performance including optics, leveling and stages, this years
update will, in detail, assess imaging, overlay and productivity performance. Based on data obtained during the
integration phase of the NXE:3100 we will assess the readiness of the system for process integration at 27nm hp and
below. Imaging performance with both conventional and off-axis illumination will be evaluated. Although single
exposure processes offer some relief, overlay requirements continue to be challenging for exposure tools. We will share
the status of the overlay performance of the NXE:3100. Source power is a key element in reaching the productivity of
the NXE:3100 - its status will be discussed as well.
Looking forward to high volume manufacturing with EUV we will update on the design status of the NXE:3300B being
introduced in 2012 with a productivity target of 125wph. Featuring a 0.33NA lens and off-axis illumination at full
transmission, a half pitch resolution from 22nm to 16nm can be supported. In order to ensure a solid volume ramp-up the
NXE:3300B will be built on as many building blocks from the NXE:3100 as possible making optimum use of the NXE
The NXE platform is a multi-generation EUV production platform that builds the technology, design and experience of
both TWINSCAN™ and the two 0.25NA EUV tools (Alpha Demo Tools or ADT's) in use at two research centers for
EUV process development. This paper reviews the EUV Industry status, presents recent imaging and device work carried
out on the two 0.25NA ADT EUV tools and the status of the 1st production tool. Shipping in 2010, the NXE:3100 will be
the 1st generation of the EUV exposure platform. With an NA of 0.25 and a productivity of 60wph this tool is targeted
for EUV process implementation and early volume production at the 27nm node. We will highlight the key features of
the NXE:3100. On our way towards shipment we describe the manufacturing status and performance data of optics,
source and stages. The 0.32NA 2nd generation tool is designed as a lithography solution for high volume manufacturing
with EUV at the 22nm node and below. With a productivity >125wph the NXE:3300 will be a cost effective solution for
Lithography at the 22nm node and below. A 3rd generation with off-axis illumination at full transmission ensures
extendibility of the NXE:3300 for resolutions down to 16nm.
Cost, cost, cost: that is what it is - ultimately - all about. Single exposure lithography is the most cost effective means of
achieving critical level exposures, and extreme ultraviolet lithography (EUVL) is the only technology that will enable
this for ≤ 27nm production. ASML is actively engaged in the development of a multi-generation production EUVL
system platform that builds on TWINSCAN<sup>TM</sup> technology and the designs and experience gained from the Alpha Demo
Tools (ADTs). The ADTs are full field step-and-scan exposure systems for EUVL and are being used at two research centers for EUVL process development by more than 10 of the major semiconductor chip makers, along with all major suppliers of masks and resist. Recently, successful implementation of EUVL for the contact hole and metal layer was demonstrated in the world's smallest (0.099 μm<sup>2</sup>) electrically functional 22nm CMOS SRAM device .
We will highlight the key features of the system description for the production platform, including the manufacturing
status of projection lens, illuminator optics, and source. Experimental results from ADT showing the progress in imaging
and resist work will be covered as well - a snapshot of imaging data can be seen in the figure below.
We will share our vision on the extendability of EUVL by discussing our system implementation roadmap. We will
explain our approach for multiple tool generations on a single platform, highlighting the ways to support the technology
nodes from 27nm half-pitch with a 0.25NA lens going down to below 16nm with a 0.32NA lens.
ASML's two alpha demo tools (ADTs) have successfully gone through acceptance testing at the customer sites. The ADTs are full field step-and-scan exposure systems for extreme ultraviolet lithography (EUVL) and are being used for EUVL process development.
The main objectives for the program are to prepare EUVL for insertion at the 27nm node, and to support the development of the global infrastructure of masks and resist.
Resolution of 28nm dense L/S has been demonstrated recently. In this paper we will look at the imaging performance of the AD-tools in comparison to the requirements for the 32nm node for Memory (NAND-Flash and DRAM) and 22nm node Logic applications, as these feature sizes can be supported by the current resist performance. Process windows and MEEF are evaluated for L/S and CHs through pitch down to 32nm half pitch. Furthermore, the full wafer CD uniformity of the critical features of a NAND-Flash gate layer at 32nm half pitch is presented as well. Based on these findings the expected imaging performance of the TWINSCAN NXE:3100 at the 27nm node will be discussed.
Single exposure lithography is the most cost effective means of achieving critical level exposures, and extreme
ultraviolet lithography (EUVL) is the technology that will enable this for 27nm production and below. ASML is actively
engaged in the development of a multi generation production EUVL system platform that builds on TWINSCAN<sup>TM</sup>
technology and the designs and experience gained from the build, maintenance, and use of the Alpha Demo Tools
(ADTs). The ADTs are full field step-and-scan exposure systems for EUVL and are being used at two research centers
for EUVL process development by more than 10 of the major semiconductor chip makers, along with all major suppliers
of masks and resist. In this paper, we will present our EUVL roadmap, and the manufacturing status of the projection
lens for our first production system. Included will also be some test data on the new reticle pods. Experimental results
from ADT showing the progress in imaging (28 nm half pitch 1:1 lines/spaces CDU ~10%), single machine overlay
down to 3 nm, and resist complete the paper.
When using the most advanced water-based immersion scanner at the 32nm node half-pitch, the image resolution will
be below the k1 limit of 0.25. In this paper, we will explore the capability of using the double pattern technique (DPT)
to extend the resolution capability of the water-based immersion lithography and examine the readiness of EUV to carry
the lithography resolution capability beyond the 32 nm HP.
The DPT, whether done in two litho and etch steps (LELE) or using the side wall spacer and sacrificial layer technique
(SPT), will require significant improvement in CDU and overlay process control performance. We will report the
experimental results in exploring the CDU and overlay performance of the LELE and the SPT options. We will also
demonstrate the need to perform full field and full wafer process corrections to compensate for dual CDU populations
and overlay entangled CDU variations.
Furthermore, we will make an assessment of EUV readiness to further extend the lithography resolution capability
beyond the 32 nm half-pitch.
The ASML extreme ultraviolet lithography (EUV) alpha demo tool is a 0.25NA fully functional lithography tool with a
field size of 26×33 mm<sup>2</sup>, enabling process development for sub-40-nm technology. Two exposure tools are installed at
customer facilities, and are equipped with a Sn discharge source. In this paper we present data measured at intermediate
focus of the Sn source-collector module. We also present performance data from both exposure tools, show the latest
results of resist exposures including excellent 32-nm half pitch dense staggered and aligned contact hole images, and
present the highlights of the first demonstration of an electrically functional full field device with one of the layers made
using EUVL in ASML's alpha demo tool.
ASML has built and shipped to The College of Nanoscale Science and Engineering of the University at Albany (CNSE)
and IMEC two full field step-and-scan exposure tools for extreme ultraviolet lithography. These tools, known as Alpha
Demo Tools (ADT), will be used for process development and to set the foundation for the commercialization of this
technology. In this paper we will present results from the set-up and integration of both ADT systems, status of resist
and reticles for EUV, and the plans for using these tools at the two research centers. We will also present the first resist
images from one of the tools at the customer site, and demonstrate 32nm half-pitch dense lines/spaces printing as well as
32nm dense contact hole printing.
The ASML EUV alpha demo tool is operational! The alpha demo tool is a 0.25NA fully functional lithography tool with a field size of 26×33 mm<sup>2</sup>, enabling process development at the 40-nm technology node. In this paper we describe the tool performance, show that vacuum is achieved in a few hours, and demonstrate that our optics contamination strategy mitigates degradation of the optics. Additional data shows the Sn source cost-of-ownership to be comparable to state-of-the-art ArF source systems, by implementing a collector contamination mitigation strategy that includes cleaning. And, we present our first 35-nm dense lines and spaces (half pitch) resist images.
As the predecessor for Extreme Ultraviolet Lithography (EUVL) production tools, ASML is realizing a development exposure tool, the alpha demo tool. The main objectives for undertaking this effort are to minimize the risks of changing to a new lithographic technology in production and to support the development of the global infrastructure of masks, sources, and resist. For this, initial imaging of the alpha demo tool is aimed at features consistent with teh 45-nm technology node. In this paper we will present the status of the realization of the alpha demo tool. Several modules of the system have been integrated in the main body, and results of the system (vacuum) performance. We will summarize the current status of EUV sources including the recent work on alternatives to using Xe, report on our in-house source research, and provide an update on the fabrication of EUV optics. Polishing data of the projection optics mirrors shows that not only have we realized the requirements for 45-nm imaging, but also are we well underway in meeting the imagin requirements for production EUVL at the 32-nm node and beyond. Finally, since key to the commercial success of EUVL will be the availability of the infrastructure for reticles and resist, we will summarize the general status of EUV masks and resist.
ASML has continued to make significant investments in the development of extreme ultraviolet lithography (EUVL), addressing the critical challenges, including defect-free mask handling, reflective optics technology, environmental control, and source. We present updates in these key areas and in the realization of our process development exposure tool. This tool is used to minimize the risk of EUVL for the 45-nm technology node and below, and to support the development of the global infrastructure of masks, sources, and resist. Realization of the process development tool is well underway; most of the modules are in vacuum qualification and functional testing. From arial image simulations, we conclude that EUVL tools are particularly suited for contact printing, due to the use of dark-field masks, and hence, limited influence of flare.
With the realization of the α-tool, ASML is progressing with the pre-commercialization phase of its EUVL development. We report on the progress in the development of several key modules of the α-tool, including the source, wafer stage and reticle stage, wafer handling, baseframe, and optics modules. We demonstrate that the focus sensor meets its vacuum requirements, and that both stages after limited servo optimization approach the required scanning performance. A particle detection system has been built for the qualification of the reticle handling module, and preliminary results show that 50nm particles can be detected. The optics lifetime program showed substantial progress by utilizing caplayers to MoSi samples in order to suppress oxidation caused by H<sub>2</sub>O molecules under EUV illumination: a suppression ≥ 100x is achieved, compared to uncapped MoSi.
Within the recently initiated EXTATIC project a complete full-field lithography exposure tool for he 50-nm technology node is being developed. The goal is to demonstrate the feasibility of extreme UV lithography (EUVL) for 50-nm imaging and to reduce technological risks in the development of EUVL production tools. We describe the EUV MEDEA+) framework in which EXTATIC is executed, and give an update on the status of the (alpha) -tool development. A brief summary of our in-house source-collector module development is given, as well as the general vacuum architecture of the (alpha) -tool is discussed. We discuss defect-free reticle handling, and investigated the uses of V-grooved brackets glued to the side of the reticle to reduce particle generation during takeovers. These takeovers do not only occur in the exposure tool, but also in multilayer deposition equipment, e-beam pattern writers, inspection tools, etc., where similar requirements on particle contamination are present. Finally, we present an update of mirror fabrication technology and show improved mirror figuring and finishing results.
Extreme ultraviolet lithography requires vacuum conditions in the optical train. In order to maintain sufficient energy throughput, reflection reduction of multilayer mirrors due to contamination has to be minimized. We report on oxidation and carbonization experiments on MoSi mirrors under exposure with EUV radiation from a synchrotron. To mimic the effects of EUV radiation we also exposed samples using an electron gun. The oxidation rate was found to be ~0.015 nm/h per mW/mm<SUP>2</SUP> of EUV radiation under vacuum conditions that are typical for a high throughput EUVL system, I.e. 10<SUP>-6</SUP> mbar H<SUB>2</SUB>O. This oxidation can to a large extend be suppressed by using smart gas blend strategies during exposure, e.g. using ethanol. A deposition rate of 0.25 nm/h was found when the hydrocarbon pressure of Fomblin was reduced to 10(superscript -9 mbar. We demonstrate that carbonization can be suppressed by admitting oxygen during electron gun exposure.
After the successful completion of the European program EUCLIDES in which core competence for Extreme UltraViolet Lithography (EUVL) technology was generated, ASML (system integration), Carl Zeiss (optics), and their partners have entered the next phase of the program: design and realization of an exposure tool called the alpha tool ((alpha) -tool). This tool should be completed in 2003, and will demonstrate 50-nm-node compliant imaging using full- field all-reflective four-times reducing optics, as well as high performance vacuum scanning wafer- and reticle stages. IN this paper we present the status of the project, as well as highlight the progress in the optics development and optics contamination mitigation efforts.